A number of Internet stocks are rallying yet again ahead of Facebook's IPO, as expectations grow for a strong debut. GOOG +2.6%. YELP +2.5%. P +2.7%. RENN +4.3%. QPSA +2.7%. DMD +6.3%. LNKD +1.8%. However, top Facebook customer Zynga (ZNGA -2.7%) is giving back some of yesterday's gains